JP6019672B2 - Liquid feeding device and method for monitoring liquid feeding device - Google Patents

Description

  The present invention relates to a method for controlling a liquid material feeding device in the food industry, medicine, chemical industry, electronic equipment manufacturing, and the like.

  Various liquid materials are used in the manufacturing field such as the food industry. In order to stabilize the quality of products using these liquid materials, it is necessary to control the amount of liquid material to be delivered with high precision, and in recent years, it has been required to deliver liquid materials more accurately and more uniformly. . For this reason, it is important to easily and accurately perform highly accurate measurement of the liquid material feeding amount and monitoring of the output state of the liquid material.

  However, when the characteristics of the liquid material fluctuate or when clogging of the liquid material occurs in each part of the liquid delivery device, the measurement accuracy of the output amount of the liquid material cannot be obtained. In particular, the occurrence of clogging with a liquid material is often caused by a short flow time of the liquid material in the circulation pipe.

  As a method for predicting the output amount to solve such problems, the actual output amount is determined from the correlation with the measurement result of the pressure at the output port, the amount of liquid delivered in the pipe, and other various measured values in the apparatus. The method is known.

  For example, in Patent Document 1, the output pressure at the output port 6 is measured as shown in FIG. 8, and the output amount is made constant by controlling the liquid feed amount so that the output pressure becomes a pressure registered in advance. A method of keeping is proposed. In this method, the relationship between the output pressure and the output amount is measured in advance, and the output amount is predicted from the output pressure.

  In Patent Document 2, as shown in FIG. 9, the output pipe 7 between the switching section 5 and the output port 6 is provided with a measuring section 4 that measures the amount of liquid fed in the output pipe 7, and the feed obtained from the measuring section 4 is provided. There has been proposed a method for measuring the output amount by the integrated value of the liquid amount.

JP 2005-288387 A JP 2011-240281 A

  However, the method of Patent Document 1 cannot accurately predict the output amount when the viscosity of the liquid material to be output changes. This is because when the viscosity changes, the flow of the liquid material changes, and the output amount changes even at the same pressure.

Moreover, in the method of patent document 2, since the fluctuation | variation of the liquid feeding amount of the output piping 7 at the time of switching of piping by the switching part 5 is too large, a liquid feeding amount cannot be measured correctly. (See Figure 10)
Moreover, in the method of Patent Document 2, when the operation of the switching unit 5 is high speed, it is difficult to measure the amount of liquid fed only for the time during which the liquid is fed to the output side due to the responsiveness of the measuring unit 5, and the switching unit It is difficult to completely suppress fluctuations in the amount of liquid delivered during 5 operations. Therefore, it is common to reduce the influence by calculating an average value for a certain time. However, when the way of flow changes for some reason of the output pipe 7 or the circulation pipe 8, the change cannot be detected by the average value for a certain period of time.

  In addition, as a general method for monitoring the change in the piping state, there is a method of measuring pressures at a plurality of positions of the piping to be monitored and monitoring the difference. However, this method cannot be monitored unless the position causing the state change is within the interval of the pressure measurement position. Further, since two or more pressure measuring devices are required, there is a problem that the equipment configuration is complicated.

  In order to solve the above-described problems, a liquid feeding device of the present invention includes a storage unit for storing a liquid material, a liquid feeding unit for feeding the liquid material outside the storage unit, and a liquid material fed from the storage unit. A liquid supply pipe serving as a flow path, a measuring unit for measuring the liquid supply pressure of the liquid substance in the liquid supply pipe, an output part for outputting the liquid substance supplied from the liquid supply pipe, and the liquid supply pipe are supplied to the output part. The output pipe that becomes the flow path for the liquid material and the circulation pipe that becomes the flow path for the liquid material collected from the liquid feed pipe to the storage section and the liquid feed pipe are at the branch point where the output pipe and the circulation pipe branch. There is a switching unit that switches the flow path of the liquid material so that the flow path communicates from the liquid piping to the output piping or the circulation piping, and a control unit that controls the liquid feeding unit and the switching unit. The monitoring unit monitors the pressure value measured by the measuring unit at the switching timing of the switching unit. From the variation, and judging the state of the circulation pipe or output tubing.

  Further, the monitoring method of the liquid feeding device of the present invention includes a liquid feeding step of feeding the liquid material stored in the storage unit to the liquid feeding pipe by driving a motor, and a liquid material supplied from the liquid feeding pipe to the output pipe. An output step for outputting from the output section through the circulation section, a circulation step for recovering the liquid substance supplied from the liquid feeding pipe to the storage section through the circulation pipe, and a liquid substance flow path from the liquid feeding pipe to the output pipe or the circulation pipe. A switching step for switching, a measuring step for measuring the liquid feeding pressure of the liquid material in the liquid feeding piping, a calculation step for calculating the amount of change in the liquid feeding pressure value before and after the channel switching timing in the liquid feeding section, and the channel switching timing It has a comparison step for comparing the change amount of the front and rear liquid supply pressure values with a predetermined set value, and a determination step for determining that the circulation piping is abnormal when the change amount is equal to or greater than the set value in the previous period.

  An object of the present invention is to solve such drawbacks, and provides a liquid feeding device capable of determining abnormalities such as clogging even if the viscosity of a liquid material changes, and a method for monitoring the liquid feeding device. There is to do.

It is a block diagram of the liquid feeding apparatus in embodiment of this invention. It is a block diagram of the control part in embodiment of this invention. It is a figure showing the relationship between the pressure in a pipe | tube at the time of a switching part of a switching part, and the output amount in an output port. It is a figure showing change of pressure value PG of measurement part 4 during change operation of change part 5 in normal time. It is a figure showing change of pressure value PG of measuring part 4 during change operation of change part 5 when clogging occurs in circulation piping. It is a figure showing change of pressure value PG of measuring part 4 during change operation of change part 5 at the time of viscosity rise of a liquid thing in the state without clogging. It is a flowchart of the monitoring method of piping in embodiment of this invention. It is a block diagram of the conventional liquid feeding apparatus. It is a block diagram of the conventional liquid feeding apparatus. FIG. 10 is a diagram illustrating fluctuations in the amount of liquid delivered to the output pipe of FIG.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing the configuration of the liquid delivery device according to the present embodiment.

  The liquid feeding device 1 includes a storage unit 2 for storing a liquid material, a liquid feeding unit 3 for feeding a liquid material from the storage unit 2, and a tubular member provided with a supply path through which the supplied liquid material passes. A piping 10, an output piping 7, a circulation piping 8), an output port 6 for outputting a liquid material, a switching unit 5 for switching a liquid feeding path, a control unit 9 for controlling the liquid feeding unit 3 and the switching unit 5, And a measuring unit 4 for measuring the liquid pressure.

  The storage unit 2 collects the liquid material supplied from the storage unit 2 at one end to the liquid supply unit 3 for supplying the liquid product to the liquid supply piping 10, and the other end collects the liquid material from the liquid supply piping 10 to the storage unit 2. It is connected to the circulation pipe 8. The liquid feeding unit 3 continuously feeds the liquid material sucked from the storage unit 2 to the liquid feeding pipe 10 by driving the motor. In the liquid feeding section 3, feedback control is performed so that the rotational speed of the motor is always the same as the set value.

  The measuring unit 4 is, for example, a pressure gauge installed in the liquid feeding pipe 10 and measures the liquid feeding pressure of the liquid material in the liquid feeding pipe 10.

  The liquid supply pipe 10 includes an output pipe 7 serving as a flow path for the liquid material supplied from the liquid supply pipe 10 to the output port 6, and a liquid material flow path for recovering the liquid material from the liquid supply pipe 10 to the storage unit 2. The circulation pipe 8 and the switching unit 5 are communicated with each other. The switching unit 5 switches the flow path so that either the output pipe 7 or the circulation pipe 8 communicates with the liquid feeding pipe 10.

  The switching unit 5 is a valve that opens and closes a flow path installed in each of the output pipe 7 and the circulation pipe 8. By controlling the opening and closing of these valves, the flow path is liquid between the storage unit 2 and the output port 6. It switches to the circulating state which circulates a thing, or the output state which outputs a liquid substance from the output port 6. FIG. The switch 51 is a valve on the output pipe 7 side, and the switch 52 is a valve on the circulation pipe 8 side. The switching operation of the switching unit 5 is performed at a desired timing by the timer of the control unit 9 during operation. The diameter of part or all of the circulation pipe 8 is smaller than the output pipe 7.

  When the liquid material is output from the output port 6, the switching unit 5 connects the flow path from the liquid feeding pipe 10 to the output pipe 7 to form an output path, and the liquid material in the storage unit 2 is connected from the liquid feeding pipe 10 to the output pipe 7. Output to the output port 6 via. When the liquid substance is not output, the switching unit 5 connects the flow path from the liquid feeding pipe 10 to the circulation pipe 8 to form a circulation path, and stores the liquid substance in the storage unit 2 from the liquid feeding pipe 10 via the circulation pipe 8. Return to part 2 and continue to circulate the liquid.

  The control unit 9 is electrically connected to the liquid feeding unit 3 and controls the operation of the liquid feeding unit 3. A value (such as the number of rotations) set by the control unit 9 is transmitted to the liquid feeding unit 3 and set to the output rotational number of the liquid feeding unit 3. The input value becomes the output rotation speed of the liquid feeding section 3, and an amount of liquid according to the rotation speed is pumped up by the liquid feeding section 3.

  The control unit 9 is electrically connected to the measuring unit 4 and acquires and stores the liquid feeding pressure of the liquid material measured by the measuring unit 4.

  The control unit 9 is electrically connected to the switching unit 5 and controls the switching unit 5. The control unit 9 sets the switching timing between the output path and the circulation path by the switching unit 5 and controls the switching unit 5 according to the timing set by a timer or the like. Furthermore, the control part 9 is provided with the monitoring part 91 which monitors a liquid feeding state.

  The liquid feeding operation of the liquid feeding device 1 will be described.

  First, the operator inputs a desired value (N) such as the motor rotation speed of the liquid feeding unit 3 to the input unit 98 of the control unit 9. In addition, the operator sets the switching timing of the switching unit 5.

  Next, the control unit 9 applies a driving voltage to the motor to rotationally drive the motor of the liquid feeding unit 3. As a result, the motor starts to rotate at the rotation speed N, and sends the liquid material supplied from the storage unit 2 to the liquid feeding pipe 10. Since the switching unit 5 is set so that the liquid supply pipe 10 communicates with the circulation pipe 8 side, the liquid material starts to circulate to the storage unit 2. Until a predetermined time elapses, the control unit 9 executes feedback control of the liquid feeding unit 3 that maintains a constant flow rate.

  Based on the initially set switching timing, the control unit 9 causes the switching unit 5 to perform a switching operation. As a result, the output of the liquid material to the output port 6 and the circulation to the storage unit 2 are alternately performed at a preset timing. When switching from the circulating state to the output state, the switching unit 51 of the switching unit 5 switches from closed to open, and when the switcher 52 switches from open to closed, a switching operation is performed to simultaneously close for a certain time.

Next, it is determined whether or not to continue liquid feeding. When it is determined that the liquid feeding is finished, the switching unit 5 is switched to the circulation pipe 8, the driving of the liquid feeding unit 3 is stopped, and the liquid feeding is finished.
When it is determined that the liquid feeding is continued, the above process is repeated until it is determined that the liquid feeding is finished.

  Next, the configuration of the monitoring unit 91 will be described in detail with reference to FIG.

  The control unit 9 includes a monitoring unit 91 that monitors the liquid supply state, and a liquid supply control unit 97 that controls the liquid supply. In addition, an input unit 98 for inputting a desired output amount in advance by the operator is provided.

The monitoring unit 91 monitors the liquid feeding state of the circulation pipe 8 and the output pipe 7 from the pressure value obtained from the measuring unit 4 and the open / closed states of the switch 51 and the switch 52.
The monitoring unit 91 includes a data acquisition unit 92, a calculation unit 93, and a determination unit 94.

  The data acquisition unit 92 acquires the switching timing of the switching unit 5 and acquires the pressure value of the liquid feeding pipe 10 measured by the measuring unit 4 according to the switching timing.

The measuring unit 4 measures the pressure at the following timing.
1. Pressure PGa of the liquid feeding pipe 10 in a state in which the switch 51 immediately before the switch 51 and the switch 52 are simultaneously closed and the switch 52 is open.
2. Pressure PGb of the liquid feeding pipe 10 during the time when the switch 51 and the switch 52 are closed simultaneously.
3. Pressure PGc of the liquid supply pipe 10 in a state in which the switch 51 immediately after the switch 51 and the switch 52 are simultaneously closed and the switch 52 is closed
The calculator 93 calculates the difference between the pressure PGa and the pressure PGc with respect to the pressure PGb.
The determination unit 94 determines the state of the circulation pipe 8 and the output pipe 7 from the pressure difference calculated by the calculation unit 93. The determination is made by comparing the difference between the data of the arithmetic unit 93 and the past data or a preset set value to determine whether there is an abnormality in the piping.

  The piping abnormality determination method in the monitoring unit 91 will be described in more detail with reference to FIG.

  FIG. 3 shows the switching operation of the switching unit 5, and the changes in the pressures of the liquid feeding pipe 10, the output pipe 7 and the circulation pipe 8, and the output amount of the liquid substance output from the output unit 6.

First, the switching operation of FIG. In FIG. 3 (a), there is no time for the switches 51 and 52 to be closed simultaneously. The flow path switches instantly. Therefore, there is no great fluctuation in the pressure of the liquid feeding pipe.
The pressure of the output pipe 7 is transmitted through the predetermined time T1. For this reason, the output amount of the liquid material from the output port 6 immediately after the switching device 51 is opened requires some time until it reaches the target output amount. Therefore, immediately after the switch 51 is opened, the output amount from the output port is reduced.

  The switching operation of FIG. 3B will be described. In FIG.3 (b), when switching from a circulation state to an output state, the time which the switch 51 and the switch 52 close simultaneously is made a fixed time.

  When the switching device 51 and the switching device 52 are closed at the same time, the outlet of the liquid feeding pipe 10 is blocked, so that the pressure of the liquid feeding pipe 10 increases.

Immediately after the switch 51 is opened and the switching unit 5 is switched to the output pipe side, the pressure of the liquid supply pipe 10 is rapidly transmitted to the output pipe 7, and the pressure of the output pipe 7 rises in a time T2 shorter than T1. For this reason, since the output amount of the liquid substance from the output port 6 immediately after the switching device 51 is opened can be rapidly increased, the time until the target output amount is reached is short, and the target and It is possible to obtain the output amount to be performed.
Note that the simultaneous closing time of the switch 51 and the switch 52 is preferably several tens to several hundreds of ms.

  A change in the pressure PG of the liquid feeding pipe 10 measured by the measuring section 4 when switching from the circulation pipe 8 side to the output pipe 7 side in the switching operation of the switching section 5 will be described with reference to FIG.

  FIG. 4 illustrates a change in the pressure value PG in the measurement unit 4 before and after switching in a normal state where no clogging has occurred.

  First, when the liquid material is flowing to the circulation pipe side (the switch 51 is closed and the switch 52 is opened), the pressure PGa is the pressure of the liquid material sent from the liquid feeding unit 3 and the switch of the switching unit 5. It is determined by the pressure loss until it returns to the storage part 2 via 52.

  Next, the pressure PGb when the outlet of the liquid supply pipe 10 is blocked (the switch 51 is closed and the switch 52 is closed) gradually increases compared to PGa. Since the liquid feeding unit 3 is feedback-controlled so as to maintain the motor speed even when the liquid material does not flow, the pressure of the liquid material rises to the extent that the maximum liquid feeding pressure of the liquid feeding unit 3 is not reached.

  When the liquid material flows to the output pipe side (the switch 51 is open and the switch 52 is closed), the pressure PGc passes through the pressure of the liquid material sent from the liquid feeding unit 3 and the switch 51 of the switching unit 5. And the pipe resistance until it is output from the output port 6. In a normal case where there is no blockage between the output ports 6 such as clogging, PGc is lower than PGb.

Next, a change in the pressure PG of the measuring unit 4 when the pipe resistance is changed in the circulation pipe 8 or the output pipe 7 will be described with reference to FIGS. 5 and 6.
FIG. 5 illustrates the pressure change before and after switching when clogging occurs in the circulation pipe 8.
In the measurement unit 4 of FIG. 5, the solid line represents the pressure change when clogging has not occurred, and the dotted line represents the pressure change when clogging has occurred in the circulation pipe 8.

  When clogging occurs, the path of the circulation pipe 8 becomes narrow. When the liquid material is flowing to the circulation pipe side (the switch 51 is closed and the switch 52 is opened), the pressure PGa is less likely to flow than before the clogging occurs, so the pipe resistance increases. . As a result, PGa greatly increases.

  When the outlet of the liquid feeding pipe 10 is blocked (the switch 51 is closed and the switch 52 is closed), the pressure PGb increases slightly or becomes equal to the pressure before clogging due to the increase in PGa.

  The pressure PGc when the liquid is flowing to the output piping side (the switch 51 is open and the switch 52 is closed) is similarly increased compared to before the occurrence of clogging.

  FIG. 6 illustrates the pressure change before and after switching when the viscosity of the liquid material increases.

  As shown in FIG. 6, when the viscosity of the liquid material increases, the pressures of PGa, PGb, and PGc increase by a certain number.

  As described above, it is not possible to distinguish whether the viscosity is increased or the path of the output pipe 7 or the circulation pipe 8 is changed by simply monitoring the PGa or PGc value. However, by monitoring the difference PGb-a between PGb and PGa or the difference PGb-c between PGb and PGc, it is possible to determine the abnormality of the pipe even under the influence of the viscosity.

The operation of the monitoring unit 91 that monitors the change in the piping path state using the measurement values PGa, PGb, and PGc of the measurement data PG of the measurement unit 4 described above will be described with reference to the flowchart of FIG.
First, in step 1, the data acquisition unit 92 collects the switching timing of the switching unit 5 and the pressure value PG of the liquid feeding pipe 10 of the measuring unit 4.

  Next, in step 2, the pressure data PGa, PGb, and PGc of the measurement unit 4 are extracted from the collected data by the calculation unit 93.

A difference PGb-a between PGb and PGa and a difference PGb-c between PGb and PGc are obtained.
At this time, the amount of change from the difference data of the previous switching unit 5 operation may be set as PGb-a and PGb-c, not just the difference.

  Next, in step 3, the determination unit 94 compares it with a threshold value set in advance for abnormality determination.

  The start of the operation of the monitoring unit 91 is, for example, from closing to opening of the switching unit 5 or switching from opening to closing, from switching unit 51 to opening or from opening to closing, or switching unit 51 and switching unit. There is a method of detecting and executing 52 simultaneous opening or simultaneous closing or performing an operation by an external trigger.

  As mentioned above, although the control method of the liquid feeding apparatus of this invention was demonstrated based on the Example, this invention is not limited to the structure described in the said Example, It combines suitably the structure described in the Example. For example, the configuration can be changed as appropriate without departing from the spirit of the invention.

Since the control method of the liquid delivery device of the present invention of the present invention has a characteristic that the liquid feed amount is controlled by simple control in feedback by monitoring the liquid feed pressure, for example, It can be suitably used for applications of liquid metering feeders such as food industry, medicine, chemical industry, and electronic equipment manufacturing.

DESCRIPTION OF SYMBOLS 1 Liquid feeding apparatus 2 Storage part 3 Liquid feeding part 4 Measuring part 5 Switching part 51 Switching part 52 Switching part 6 Output port 7 Output piping 8 Circulation piping 9 Control part 10 Liquid feeding piping 91 Monitoring part 92 Data acquisition part 93 Calculation part 94 Judgment unit 97 Liquid feed control unit 98 Input unit

Claims (3)

A storage section for storing a liquid material;
A liquid feeding section for feeding the liquid to the outside of the storage section;
A liquid supply pipe serving as a flow path for the liquid material supplied from the storage unit;
The liquid material supplied to the output unit from the measurement unit that measures the liquid supply pressure of the liquid material in the liquid supply pipe, the output unit that outputs the liquid material supplied from the liquid supply pipe, and the liquid supply pipe An output pipe to be a flow path of the liquid and a circulation pipe to be a flow path of the liquid material collected from the liquid supply pipe to the storage unit;
The liquid supply pipe is at a branch point that branches into the output pipe and the circulation pipe.
A switching unit that switches the flow path of the liquid material so that the flow path communicates from the liquid supply pipe to the output pipe or the circulation pipe;
A controller that controls the liquid feeding unit and the switching unit;
The control unit further includes a monitoring unit for monitoring a liquid feeding state,
The monitoring unit is a liquid feeding device that determines the state of the circulation piping or the output piping from the amount of change in the pressure measurement value of the measuring unit at the switching timing of the switching unit.
Because
The switching unit is a valve provided in each of the output pipe and the circulation pipe,
Switching the flow path by opening and closing the valve of the output pipe and the valve of the circulation pipe,
The measuring unit includes a pressure PGa of a liquid supply pipe in a state where the valve of the output pipe is closed and the valve of the circulation pipe is open immediately before the valve of the output pipe and the valve of the circulation pipe are simultaneously closed, and the output The pressure PGb of the liquid supply piping at the time when the valve of the piping and the valve of the circulation piping are simultaneously closed, the valve of the output piping immediately after the valve of the output piping and the valve of the circulation piping are simultaneously closed and the Measure the pressure PGc of the liquid supply pipe with the valve of the circulation pipe closed,
The monitoring unit calculates a change amount of the pressure measurement values PGa, PGb, PGc;
The liquid delivery device further comprising a determination unit that compares the amount of change in the pressure measurement value calculated by the calculation unit with a predetermined set value . The liquid delivery device according to claim 1 ,
The calculation unit obtains a change amount of the pressure measurement values PGb and PGa,
The determination unit determines that the circulation pipe is abnormal when the change amount is smaller than the set value. A liquid feeding step for feeding the liquid material stored in the storage unit to the liquid feeding pipe by driving a motor;
An output step of outputting the liquid material supplied from the liquid supply pipe from an output section through an output pipe;
A circulation step of recovering the liquid material supplied from the liquid supply pipe to the storage unit through a circulation pipe;
A switching step of switching the flow path by opening and closing the valve of the output pipe and the valve of the circulation pipe ;
The pressure PGa of the liquid supply pipe in a state in which the valve of the output pipe is closed and the valve of the circulation pipe is open immediately before the valve of the output pipe and the valve of the circulation pipe are simultaneously closed, the valve of the output pipe, and the The pressure PGb of the liquid supply pipe at the time when the valves of the circulation pipe are simultaneously closed, the valve of the output pipe immediately after the valve of the output pipe and the valve of the circulation pipe are simultaneously closed, and the valve of the circulation pipe are A measurement step for measuring the pressure PGc of the liquid supply pipe in the closed state ;
A calculation step of calculating a change amount of the pressure measurement values PGa, PGb, PGc ;
A comparison step of comparing the calculated change amount of the pressure measurement value with a predetermined set value ;
A method for monitoring a liquid delivery device, comprising:

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